Hypophosphatemia in Enterally Fed Patients in the Surgical Intensive Care Unit: Common but Unrelated to Timing of Initiation or Aggressiveness of Nutrition Delivery

Incidence of hypophosphataemia after ICU admission in mechanically ventilated patients and its relationship with risk factors for refeeding syndrome

OBJECTIVE

To describe the incidence of hypophosphatemia in patients admitted to the ICU who have required mechanical ventilation. To analyze the presence of risk factors and its relationship with nutritional practice.

DESIGN

Prospective observational study.

SETTING

Polyvalent ICUs of 2 University Hospitals.

PATIENTS OR PARTICIPANTS

Patients on invasive mechanical ventilation ≥72 h with normal level of phosphorus at admission.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

Electrolyte levels (phosphorus, magnesium, potassium) were determined on admission to the ICU and at 96 h. Risk categories on admission, caloric intake, insulin doses and acid-base status during the first 4 days of admission were recorded. Incidence was calculated as the number of patients who developed hypophosphataemia after admission. Univariate analysis was performed for between-group comparison and multivariate analysis of potential risk factors.

RESULTS

89 patients were included. The incidence of hypophosphataemia was 32.6%. In these patients phosphorus decreased from 3.57 ± 1.02 mmol/l to 1.87 ± 0.65 mmol/l (52.3%). The mean kcal/kg/24 h provided in the first 4 days was 17.4 ± 4.1, with no difference between the group that developed hypophosphataemia and the group that did not. Significant risk factors were insulin doses administered and pH and PaCO2 values.

CONCLUSIONS

The incidence of hypophosphataemia at 96 h from admission in mechanically ventilated patients is high and unrelated to the risk category and hypocaloric nutritional practice used. Insulin dosis and acid-base status are the main determinants of its occurrence.

Hypophosphatemia after Start of Medical Nutrition Therapy Indicates Early Refeeding Syndrome and Increased Electrolyte Requirements in Critically Ill Patients but Has No Impact on Short-Term Survival

Refeeding syndrome (RFS) is a potentially life-threatening complication in malnourished (critically ill) patients. The presence of various accepted RFS definitions and the inclusion of heterogeneous patient populations in the literature has led to discrepancies in reported incidence rates in patients requiring treatment at an intensive care unit (ICU). We conducted a prospective observational study from 2010 to 2013 to assess the RFS incidence and clinical characteristics among medical ICU patients at a large tertiary center. RFS was defined as a decrease of more than 0.16 mmol/L serum phosphate to values below 0.65 mmol/L within seven days after the start of medical nutrition therapy or pre-existing serum phosphate levels below 0.65 mmol/L. Overall, 195 medical patients admitted to the ICU were included. RFS was recorded in 92 patients (47.18%). The presence of RFS indicated significantly altered phosphate and potassium levels and was accompanied by significantly more electrolyte substitutions (phosphate, potassium, and magnesium). No differences in fluid balance, energy delivery, and insulin requirements were detected. The presence of RFS had no impact on ICU length of stay and ICU mortality. Screening for RFS using simple diagnostic criteria based on serum phosphate levels identified critically ill patients with an increased demand for electrolyte substitutions. Therefore, stringent monitoring of electrolyte levels is indicated to prevent life-threatening complications.

Assessment of refeeding syndrome definitions and 30-day mortality in critically ill adults: A comparison study

BACKGROUND

Patients in the intensive care unit (ICU) are at high risk for refeeding syndrome (RFS), yet there is uncertainty regarding how RFS should be operationalized in the ICU. We evaluated different definitions for RFS and tested how they associated with patient-centered outcomes in the ICU.

METHODS

This was a retrospective comparison study. Patients age ≥18 years were eligible if they were newly initiated on enteral feeding while hospitalized in the ICU. Eight definitions for RFS were operationalized, including that from the American Society for Parenteral and Enteral Nutrition (ASPEN), all based on electrolyte levels from immediately before until up to 5 days after the initiation of enteral nutrition. Patients were followed for death or for ICU-free days, a measure of healthcare utilization.

RESULTS

In all, 2123 patients were identified, including 406 (19.1%) who died within 30 days of ICU admission and 1717 (80.9%) who did not. Prevalence of RFS varied from 1.5% to 88% (ASPEN definition) depending on the RFS definition used. The excess risk for death associated with RFS varied from 33% to 92% across definitions. The development of RFS based on the ASPEN definition was associated with a greater decrease in ICU-free days compared with other definitions, but the relationship was not statistically significant.

CONCLUSION

Eight definitions for RFS were evaluated, none of which showed strong associations with death or ICU-free days. It may be challenging to achieve a standardized definition for RFS that is based on electrolyte values and predicts mortality or ICU-free days.

Impact of Nutritional Management on Survival of Critically Ill Malnourished Patients with Refeeding Hypophosphatemia

BACKGROUND

Early nutritional therapy may aggravate hypophosphatemia in critically ill patients.

AIM

To investigate the influence of the type nutritional therapy on the survival of critically-ill malnourished patients at refeeding hypophosphatemia risk.

METHODS

Retrospective cohort study including malnourished, critically-ill adults, admitted from June 2014-December 2017 in an intensive care unit (ICU) at a tertiary hospital. Refeeding hypophosphatemia risk was defined as low serum phosphorus levels (<2.5 mg/dL) seen at two timepoints: before the initiation and at day 4 of the nutritional therapy. Patients receiving enteral nutrition (EN) were compared with those receiving supplemental parenteral nutrition (SPN-EN plus parenteral nutrition). Primary outcome was 60 d survival. Secondary endpoint was the incidence of refeeding hypophosphatemia risk.

RESULTS

We included 468-321 patients (68.6%) received EN and 147 (31.4%) received SPN. The mortality rate was 36.3% (n = 170). Refeeding hypophosphatemia risk was found in 116 (24.8%) patients before and in 177 (37.8%) at day 4 of nutritional therapy. The 60 d mean survival probability was greater for patients receiving SPN both before (42.4 vs. 22.4%, p = 0.005) and at day 4 (37.4 vs. 25.8%, p = 0.014) vs. patients receiving EN at the same timepoints. Cox regression showed a hazard ratio of 3.3 and 2.4 for patients at refeeding hypophosphatemia risk before and at day 4 of EN, respectively, compared to the SPN group at the same timepoints.

CONCLUSION

Refeeding hypophosphatemia risk was frequent in malnourished ICU patients and the survival for patients receiving SPN seemed associated with better survival than EN only.

Development and validation of risk prediction model for refeeding syndrome in neurocritical patients

Background

The incidence of refeeding syndrome (RFS) in critically ill patients is high, which is detrimental to their prognoses. However, the current status and risk factors for the occurrence of RFS in neurocritical patients remain unclear. Elucidating these aspects may provide a theoretical basis for screening populations at high risk of RFS.

Methods

A total of 357 patients from January 2021 to May 2022 in a neurosurgery ICU of a tertiary hospital in China were included using convenience sampling. Patients were divided into RFS and non-RFS groups, based on the occurrence of refeeding-associated hypophosphatemia. Risk factors for RFS were determined using univariate and logistic regression analyses, and a risk prediction model for RFS in neurocritical patients was developed. The Hosmer-Lemeshow test was used to determine the goodness of fit of the model, and the receiver operator characteristic curve was used to examine its discriminant validity.

Results

The incidence of RFS in neurocritical patients receiving enteral nutrition was 28.57%. Logistic regression analyses showed that history of alcoholism, fasting hours, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, Sequential Organ Failure Assessment (SOFA) scores, low serum albumin, and low baseline serum potassium were risk factors of RFS in neurocritical patients (p < 0.05). The Hosmer-Lemeshow test showed p = 0.616, and the area under the ROC curve was 0.791 (95% confidence interval: 0.745-0.832). The optimal critical value was 0.299, the sensitivity was 74.4%, the specificity was 77.7%, and the Youden index was 0.492.

Conclusion

The incidence of RFS in neurocritical patients was high, and the risk factors were diverse. The risk prediction model in this study had good predictive effects and clinical utility, which may provide a reference for assessing and screening for RFS risk in neurocritical patients.

Trauma-related electrolyte disturbances: From resuscitation to rhabdomyolysis

Traumatic injury results in drastic changes to a patient's normal physiology. The hormonal stress response, as well as some treatment strategies, lead to significant disruptions in electrolyte homeostasis that are important for clinicians to understand. In addition, advances in fluid resuscitation and modern transfusion practices have led to their own unique set of consequences, which we are just beginning to appreciate. Special attention is placed on rhabdomyolysis, as this distinct entity represents an extreme example of injury induced electrolyte derangements. This review describes the physiologic response to trauma and highlights some of the important electrolyte abnormalities that can be encountered while caring for the injured patient.

Serum Lactate Dehydrogenase to Phosphate Ratio as an Independent Predictor for Adverse Outcome of Microsurgical Clipping for Ruptured Intracranial Aneurysm: A Propensity-Score Matching Analysis

Objective: In this study, we assessed the correlation between the lactate dehydrogenase (LDH) to phosphate ratio and the prognosis of microsurgical clippings for ruptured intracranial aneurysm (rIA) to test the hypothesis that the serum LDH to phosphate ratio could be a predictor of the outcome of microsurgical clipping for rIA. Methods: Records of rIA patients between 2012 and 2018 were retrospectively collected. Age, sex, Hunt-Hess grade, Fisher grade, medical history, aneurysm location, hydrocephalus, laboratory data including serum LDH, phosphate, and LDH to phosphate ratio, related complications, and the outcomes in 3 months were recorded. Results: A total of 1608 rIA patients in our institution were collected, and 856 patients treated by microsurgical clipping were enrolled. On admission, a significantly higher LDH-phosphate ratio was observed in patients with poor outcomes at 3 months (median ± SD, 200.175 ± 107.290 for mRS 0−2 vs. 323.826 ± 219.075 for mRS score 3−6; p = 0.000). An LDH to phosphate ratio of 226.25 in the receiver operating characteristic (ROC) curve was the optimal cutoff value to discriminate between good and poor outcomes at 3 months. The LDH to phosphate ratio ≥ 226.25 on admission was independently correlated with poor outcomes in rIA patients. In addition, Hunt and Hess grade, Fisher grade, pneumonia, and DIND were also independently correlated with poor outcomes. After removing the bias in essential clinical variables between patients with LDH to phosphate, ratio ≥ 226.25 versus <226.25 by PSM, the number of patients with poor outcomes at 3 months increased in patients with an LDH to phosphate ratio of ≥226.25 (p = 0.005). Conclusions: The LDH to phosphate ratio was a potential biomarker and could predict the unfavorable outcome of microsurgical clipping for rIA in 3 months, related to neuronal damage, cerebral hypoxia, and early brain injury after aneurysm ruptures.

Refeeding syndrome in surgical patients post initiation of artificial feeding, a prospective cohort study in a low-income country

BACKGROUND & AIMS

South Africa's inequitable history has contributed to a malnourished population, further aggravated by high levels of violence and economic uncertainty culminating in a population suffering the sequelae of poverty. The perceived notion is that malnutrition places the South African population at greater risk for development of refeeding syndrome. This study aimed to identify the incidence of refeeding syndrome in the South African population.

METHODS

All patients admitted into the surgical intensive care unit from 1 November 2019 to 30 September 2020, were screened using the National Institute for Health and Care Excellence (NICE) refeeding risk criteria. Patients started on artificial feeds with one or more risk factors were included in the study. The syndrome was confirmed using the King's College criteria and compared with the American Society for Parenteral and Enteral Nutrition (ASPEN) criteria for refeeding syndrome.

RESULTS

200 Patients were included in this study. The median age of the sample population was 41 years (IQR 30-58) with a male predominance (63%). All patients included had one or more risk factors and 62 (31%) of patients fulfilled the NICE criteria. The sensitivity of the NICE criteria was 33% and specificity was 70%. The most common risk factors identified were little or no nutritional intake for >5 days (55%) followed by a history of alcohol abuse, drugs including insulin, chemotherapy, diuretics or antacids (18%). Specificity values for all risk factors were >80% apart from little or no nutritional intake for >5 days which had a specificity of 64.2%. Sensitivity values for all risk factors were low. 84.5% of patients received artificial nutritional support in the form of enteral feeds, 9% parenteral and 6.5% both enteral and parenteral feeds. A total of 146 patients required electrolyte supplementation. Three patients fulfilled the King's College criteria and one subsequently died. In comparison, 25 patients fulfilled the ASPEN criteria and 3 demised.

CONCLUSION

Due to the low sensitivity and specificity of the NICE criteria, we advise that it be used merely as a guideline to identify patients at risk of refeeding syndrome and one should remain vigilant in patients with any risk factors present. Due to the small number of patients who fulfilled the King's College criteria and significant difference in incidence when compared to the ASPEN definition, a conclusion regarding the accuracy of both diagnostic criteria could not be made. We recommend a review of the current definition and a global adoption of an agreed criteria for the estimation of the true prevalence.

Impact of Refeeding Syndrome on Short- and Medium-Term All-Cause Mortality: A Systematic Review and Meta-Analysis

BACKGROUND

The refeeding syndrome has been described as a potentially life-threatening complication of renutrition. However, moving from single reports to larger population studies, the real impact of refeeding syndrome on all-cause mortality is still unknown.

METHODS

PubMed/Medline, EMBASE, Cochrane library, and CINAHL databases were systematically searched until September 2020 for studies reporting mortality rates in patients who developed the syndrome at renutrition compared with those who did not develop it. Effect sizes were pooled through a random-effect model.

RESULTS

Thirteen studies were finally considered in the meta-analysis, for a total of 3846 patients (mean age 64.5 years; 58% males). Pooled data showed a nonsignificant trend toward an increased short-term (≤1 month) mortality in patients developing the refeeding syndrome (odds ratio = 1.27, 95% confidence interval 0.93-1.72), mostly driven by studies in which renutrition was not prescribed and supervised by a nutritional support team (P = .01 at subgroup analysis) and by studies published in previous years (P = .04 at meta-regression). When examining medium-term (≤6 month) mortality, an overall statistical significance toward higher risk was observed (odds ratio = 1.54, 95% confidence interval 1.04-2.28).

CONCLUSION

This was the first meta-analysis that specifically assessed the impact of refeeding syndrome on mortality. Our results suggested a nonsignificant trend toward increased mortality in the short term but a significantly increased mortality in the medium term. The supervision/management of the refeeding process by a nutrition specialist might be a key factor for the limitation of this mortality excess.

An unexpectedly high incidence of refeeding syndrome in patients with total parenteral nutrition in a reference university hospital

INTRODUCTION

Refeeding syndrome occurs with the reintroduction of food after an individual has undergone a substantial period of malnutrition. The development of this condition is not uncommon but is neglected in most cases.

OBJECTIVE

To identify the incidence of refeeding syndrome in hospitalized patients undergoing total parenteral nutrition and factors that may be associated with this condition.

MATERIALS AND METHODS

Observational retrospective and prospective cohort study. Data collection took place at the Hospital de Clínicas de Porto Alegre, from 2015 to 2018. Data was collected consecutively from patient electronic medical records. All hospitalized individuals aged 18 years or more and having a prescription for total parenteral nutrition were included in the study. Exclusion criteria included patients with diabetic ketoacidosis; receiving renal replacement therapy or chronic kidney disease with a glomerular filtration rate <30 mL/min; severe metabolic acidosis or any disease that could affect serum phosphorus levels. WinPepi software, version 11.65, was used to calculate sample size. Data analysis was performed using SPSS version 20.0. A 5% significance level was considered for the established comparisons. The project was approved by the Research Ethics Committee of Hospital de Clínicas de Porto Alegre (number 17-0313).

RESULTS

Data from 97 patients was collected. The incidence of refeeding syndrome in our sample was 43.3% (n = 42). Factors positively associated with the syndrome were use of standard parenteral nutrition (p < 0.01), advancing age (mean 62.8 yr versus 55.1 yr; p = 0.013), and amount of total energy administered, which were 25.6 kcal/kg/day versus 23.6 kcal/kg/day for patients with and without refeeding syndrome, respectively (p < 0.01).

CONCLUSION

The incidence of refeeding syndrome in individuals using total parenteral nutrition was high. The supply of a greater quantity of total energy in the first week of nutritional therapy, the absence of electrolytes in the parenteral nutrition solution and advancing age were all factors associated with the emergence of refeeding syndrome.

A comparison of two different refeeding protocols and its effect on hand grip strength and refeeding syndrome: a randomized controlled clinical trial

PURPOSE

Optimal refeeding protocols in older malnourished hospital patients remain unclear. We aimed to compare the effect of two different refeeding protocols; an assertive and a cautious protocol, on HGS, mortality and refeeding syndrome (RFS), in patients ≥ 65 years METHODS: Patients admitted under medical or surgical category and at risk of RFS, were randomized to either an enteral nutrition (EN) refeeding protocol of 20 kcal/kg/day, reaching energy goals within 3 days (intervention group), or a protocol of 10 kcal/kg/day, reaching goals within 7 days (control group). Primary outcome was the difference in hand grip strength (HGS) at 3 months follow-up, in an intention to treat analysis. RFS (phosphate < 0.65 mmol/L) during the hospital stay and mortality rates at 3 months were secondary outcomes.

RESULTS

A total of 85 patients were enrolled, with mean (SD) age of 79.8(7.4) and 54.1% female, 41 in the intervention group and 44 in the control group. HGS was similar at 3 months with mean change of 0.42 kg (95% CI - 2.52 to 3.36, p = 0.78). Serum phosphate < 0.65 mmol/L was seen in 17.1% in the intervention group and 9.3% in the control group, p = 0.29. There was no difference in mortality rates (39% vs 34.1%, p = 0.64). An indication of more respiratory distress was found in the intervention group, 53.6% vs 30.2%, p = 0.029.

CONCLUSION

A more assertive refeeding protocol providing 20 kcal/kg/day did not result in improved HGS measured 3 months after discharge compared with a cautious refeeding (10 kcal/kg/day) protocol. No difference in incidence of mortality or RFS was found.

TRIAL REGISTRATION

ClinicalTrials.gov Protocol Record 2017/FO148295, Registered: 21st of February, 2017.

The incidence of the refeeding syndrome. A systematic review and meta-analyses of literature

BACKGROUND & AIMS

The refeeding syndrome (RFS) has been recognized as a potentially life-threatening metabolic complication of re-nutrition, but the definition widely varies and, its incidence is unknown. The aim of this systematic review and meta-analyses was to estimate the incidence of RFS in adults by considering the definition used by the authors as well as the recent criteria proposed by the American Society of Parenteral and Enteral Nutrition (ASPEN) consensus. Furthermore, the incidence of refeeding hypophosphatemia (RH) was also assessed.

METHODS

Four databases were systematically searched until September 2020 for retrieving trials and observational studies. The incidences of RFS and RH were expressed as percentage and reported with 95% confidence intervals (CI).

RESULTS

Thirty-five observational studies were included in the analysis. The risk of bias was serious in 16 studies and moderate in the remaining 19. The incidence of RFS varied from 0% to 62% across the studies. No substantial change in the originally reported incidence of RFS was found by applying the ASPEN criteria. Similarly, the incidence of RH ranged between 7% and 62%. In the subgroup analyses, inpatients from Intensive Care Units (ICUs) and those initially fed with >20 kcal/kg/day seemed to have a higher incidence of both RFS (pooled incidence = 44%; 95% CI 36%-52%) and RH (pooled incidence = 27%; 95% CI 21%-34%). However, due to the high heterogeneity of data, summary incidence measures are meaningless.

CONCLUSION

The incidence rate of both RFS and RH greatly varied according to the definition used and the population analyzed, being higher in ICU inpatients and in those with increased initial caloric supply. Therefore, a universally accepted definition for RFS, taking different clinical contexts and groups of patients into account, is still needed to better characterize the syndrome and its approach.

Electrolyte disorders during the initiation of nutrition therapy in the ICU

PURPOSE OF REVIEW

To summarize recent evidence on prevalence, risk factors, significance, treatment, and prevention of electrolyte disorders in critically ill with a specific focus on disorders during the initiation of nutrition.

RECENT FINDINGS

Electrolyte disturbances appear to occur often during critical illness, and most of them seem to be associated with impaired outcome. However, a recent systematic review indicated insufficient evidence to answer clinically relevant questions regarding hypophosphatemia. Similar questions (which thresholds of serum levels are clinically relevant; how serum levels should be corrected and how do different correction regimens/approaches influence outcome) are not clearly answered also for other electrolytes. The most crucial feature of electrolyte disturbances related to feeding is refeeding syndrome. Recent evidence supports that additionally to the correction of electrolyte levels, a temporary restriction of calories (reducing the magnitude of this metabolic feature, including electrolyte shifts) may help to improve outcome.

SUMMARY

Diverse electrolyte disorders often occur in critically ill patients. Hypophosphatemia, hypokalemia, and hypomagnesemia that are encountered after initiation of feeding identify refeeding syndrome. Along with correction of electrolytes, reduction of caloric intake may improve the outcome of the refeeding syndrome.

Refeeding risks in patients requiring intravenous nutrition support: Results of a two-centre, prospective, double-blind, randomised controlled trial

BACKGROUND/AIMS

Refeeding syndrome can result following excessive feeding of malnourished patients. The syndrome remains poorly defined but encompasses a range of adverse effects including electrolyte shifts, hyperglycaemia and other less well-defined phenomena. There are additional risks of underfeeding malnourished individuals. Studies of refeeding syndrome have generally focussed on critical care environments or patients with anorexia nervosa. Here we have conducted a two-centre, prospective, double-blind, randomised controlled trial amongst all patients referred to hospital nutrition support teams for intravenous nutrition support. We sought to determine whether electrolyte and other abnormalities suggestive of refeeding syndrome risk varied depending on initial rate of intravenous feeding.

METHODS

Patients at moderate or high risk of refeeding syndrome, as defined by United Kingdom National Institute of Health and Care Excellence guidelines, were screened for inclusion. Patients were randomised to receive either high (30 kcal/kg/day, 0.25 gN/kg/day) or low (15 kcal/day, 0.125 gN/kg/day) rate feeding for the first 48 h prior to escalation to standard parenteral nutrition regimens. The primary outcome was rates of potential refeeding risks within the first 7 days as defined by electrolyte imbalance or hyperglycaemia requiring insulin. Secondary outcomes included effects on QTc interval, infections and length of hospital stay. Statistical analysis was performed with χ² or Wilcoxon rank sum tests and all analysis was intention-to-treat. Problems with study recruitment led to premature termination of the trial. Registered on the EU Clinical Trials Register (EudraCT number 2007-005547-17).

RESULTS

534 patients were screened and 104 randomised to either high or low rate feeding based on risk of refeeding syndrome. Seven patients were withdrawn prior to collection of baseline demographics and were excluded from analysis. 48 patients were analysed for the primary outcome with potential refeeding risks identified in 46%. No differences in risks were seen between high and low rate feeding (p > 0.99) or high and moderate risk feeding (p = 0.68). There were no differences in QTc abnormalities, infection rates, or hospital length of stay between groups.

CONCLUSIONS

In this randomised trial of rates of refeeding risk, in patients pre-stratified as being at high or moderate risk, we found no evidence of increased refeeding related disturbances in those commenced on high rate feeding compared to low rate. No differences were seen in secondary endpoints including cardiac rhythm analysis, infections or length of stay. Our study reflects real world experience of patients referred for nutrition support and highlights challenges encountered when conducting clinical nutrition research.

The Refeeding Syndrome: a neglected but potentially serious condition for inpatients. A narrative review

The Refeeding Syndrome (RFS) is a potentially serious, but still overlooked condition, occurring in individuals who are rapidly fed after a period of severe undernourishment. RFS derives from an abnormal electrolyte and fluid shifts leading to many organ dysfunctions. Symptoms generally appear within 2-5 days of re-feeding and may be absent/mild or severe and life threating, depending on the pre-existing degree of malnutrition and comorbidities. The lack of a standard definition and the nonspecificity of the symptoms make both incidence estimate and diagnosis difficult. In 2020, the American Society for Parenteral and Enteral Nutrition (ASPEN) proposed a unifying definition for the RFS and its severity classification. The awareness of the condition is crucial for identifying patients at risk, preventing its occurrence, and improving the management. The objectives of this narrative review were to summarize the current knowledge and recommendations about the RFS and to provide useful tips to help physicians to recognize and prevent the syndrome.

Risks in Management of Enteral Nutrition in Intensive Care Units: A Literature Review and Narrative Synthesis

Critically ill patients in the intensive care unit (ICU) have a high risk of developing malnutrition, and this is associated with poorer clinical outcomes. In clinical practice, nutrition, including enteral nutrition (EN), is often not prioritized. Resulting from this, risks and safety issues for patients and healthcare professionals can emerge. The aim of this literature review, inspired by the Rapid Review Guidebook by Dobbins, 2017, was to identify risks and safety issues for patient safety in the management of EN in critically ill patients in the ICU. Three databases were used to identify studies between 2009 and 2020. We assessed 3495 studies for eligibility and included 62 in our narrative synthesis. Several risks and problems were identified: No use of clinical assessment or screening nutrition assessment, inadequate tube management, missing energy target, missing a nutritionist, bad hygiene and handling, wrong time management and speed, nutritional interruptions, wrong body position, gastrointestinal complication and infections, missing or not using guidelines, understaffing, and lack of education. Raising awareness of these risks is a central aspect in patient safety in ICU. Clinical experts can use a checklist with 12 identified top risks and the recommendations drawn up to carry out their own risk analysis in clinical practice.

Hypophosphatemia and risk of refeeding syndrome in critically ill patients before and after nutritional therapy

OBJECTIVE

To investigate the prevalence of hypophosphatemia as a marker of refeeding syndrome (RFS) before and after the start of nutritional therapy (NT) in critically ill patients.

METHODS

Retrospective cohort study including 917 adult patients admitted at the intensive care unit (ICU) of a tertiary hospital in Cuiabá-MT/Brasil. We assessed the frequency of hypophosphatemia (phosphorus <2.5mg/dl) as a risk marker for RFS. Serum phosphorus levels were measured and compared at admission (P1) and after the start of NT (P2).

RESULTS

We observed a significant increase (36.3%) of hypophosphatemia and, consequently, a greater risk of RFS from P1 to P2 (25.6 vs 34.9%; p<0.001). After the start of NT, malnourished patients had a greater fall of serum phosphorus. Patients receiving NT had an approximately 1.5 times greater risk of developing RFS (OR= 1.44 95%CI 1.10-1,89; p= 0.01) when compared to those who received an oral diet. Parenteral nutrition was more associated with hypophosphatemia than either enteral nutrition (p=0,001) or parenteral nutrition supplemented with enteral nutrition (p=0,002).

CONCLUSION

The frequency of critically ill patients with hypophosphatemia and at risk for RFS on admission is high and this risk increases after the start of NT, especially in malnourished patients and those receiving parenteral nutrition.

Hypophosphatemia in critically ill adults and children - A systematic review

BACKGROUND & AIMS

Phosphate is the main intracellular anion essential for numerous biological processes. Symptoms of hypophosphatemia are non-specific, yet potentially life-threatening. This systematic review process was initiated to gain a global insight into hypophosphatemia, associated morbidity and treatments.

METHODS

A systematic review was conducted (PROSPERO CRD42020163191). Nine clinically relevant questions were generated, seven for adult and two for pediatric critically ill patients, and prevalence of hypophosphatemia was assessed in both groups. We identified trials through systematic searches of Medline, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, and Web of Science. Quality assessment was performed using the Cochrane risk of bias tool for randomized controlled trials and the Newcastle-Ottawa Scale for observational studies.

RESULTS

For all research questions, we identified 2727 titles in total, assessed 399 full texts, and retained 82 full texts for evidence synthesis, with 20 of them identified for several research questions. Only 3 randomized controlled trials were identified with two of them published only in abstract form, as well as 28 prospective and 31 retrospective studies, and 20 case reports. Relevant risk of bias regarding selection and comparability was identified for most of the studies. No meta-analysis could be performed. The prevalence of hypophosphatemia varied substantially in critically ill adults and children, but no study assessed consecutive admissions to intensive care. In both critically ill adults and children, several studies report that hypophosphatemia is associated with worse outcome (prolonged length of stay and the need for respiratory support, and higher mortality). However, there was insufficient evidence regarding the optimal threshold upon which hypophosphatemia becomes critical and requires treatment. We found no studies regarding the optimal frequency of phosphate measurements, and regarding the time window to correct hypophosphatemia. In adults, nutrient restriction on top of phosphate repletion in patients with refeeding syndrome may improve survival, although evidence is weak.

CONCLUSIONS

Evidence on the definition, outcome and treatment of clinically relevant hypophosphatemia in critically ill adults and children is scarce and does not allow answering clinically relevant questions. High quality clinical research is crucial for the development of respective guidelines.

Refeeding Syndrome in Patients Receiving Parenteral Nutrition Is Not Associated to Mortality or Length of Hospital Stay: A Retrospective Observational Study

BACKGROUND

Refeeding syndrome (RS) is characterized by severe electrolyte derangement that may be associated with worse clinical outcomes in hospitalized patients. In this study, we aim to assess the incidence of RS in inpatients receiving parenteral nutrition (PN) and its possible association with the length of hospital stay (LHS) and mortality.

METHODS

We conducted a historical cohort study involving adults receiving PN, monitored by a nutrition therapy team in a Brazilian public hospital. Data collection was made from electronic records. We assessed the presence of RS after PN therapy was initiated. The amount of energy delivered within 72 hours of PN, LHS, and mortality were compared between patients with and without RS.

RESULTS

One-hundred ninety-seven patients (aged 57.7 ± 14.1 years; 55.7% men) were followed for a median of 51 days. The incidence of RS was equal to 25.4%. The adequacy of energy delivered in relation to energy requirements within 72 hours (69.4% ± 29.3% vs 61.8% ± 21.6%) was higher in patients with RS than in those without RS (P = .054). The incidence of death was 55.3% and did not differ between groups. The median of LHS was equal to 51.0 (32.0-83.0) days, and it also did not differ between patients with and without RS.

CONCLUSION

RS was identified in 25% of patients receiving PN, but it was not associated to mortality and LHS, even when energy delivery was considered in combination to RS.

Impact of hypophosphatemia on outcome of patients in intensive care unit: a retrospective cohort study

Background

Hypophosphatemia generally occurs in Intensive Care Units (ICUs), but its impact is often ignored. The aim of this study was to investigate whether hypophosphatemia can be a risk factor for ICU 28-day mortality.

Methods

A single-center retrospective cohort study was conducted by collecting data from 1073 patients admitted to general ICU and then presented to the Sixth Affiliated Hospital, Sun Yat-sen University (Guangzhou City, Guangdong Province, China) from 1 January 2016 to 31 December 2017. The patients were divided into a normal control group (serum phosphate levels 0.80–1.60 mmol/L) and a hypophosphatemia group (serum phosphate levels < 0.80 mmol/L), based on the concentration of phosphorus at the time of ICU admission. The association between phosphate levels and ICU 28-day mortality was evaluated by binary logistic regression analysis. Multivariate logistic regression was employed to predict the ICU 28-day mortality.

Results

The cohort included 946 patients with a median phosphate concentration of 0.77 mmol/L (interquartile range 0.55–1.03 mmol/L). Patients with hypophosphatemia had a higher ICU 28-day mortality than the normal control group (33.3% vs 24.0%, P < 0.05). Patients with hypophosphatemia had a longer ICU and hospital stays, and prolonged duration of mechanical ventilation (all P < 0.05). Hypophosphatemia was an independent risk factor for ICU 28-day mortality (adjusted OR = 1.5, 95% CI = 1.1–2.1, P = 0.01) in the multivariate logistic regression analysis.

Conclusions

Hypophosphatemia at admission is an independent risk factor for 28-day mortality in general ICU patients.

Trial registration

The medical study was approved by the Institutional Ethics Committee of the Six Affiliated Hospital, Sun Yat-sen University (Approval number: 2017ZSLYEC-110). No consent was given as the data were analyzed anonymously.

Risk of refeeding syndrome. Case report

Introduction: Refeeding syndrome is an acute metabolic disorder that occurs during nutritional repletion. Although it has been known for years, the early detection of risk factors for its onset and the implementation of measures to prevent it are not common in nutritional care.Case presentation: 48-year-old male patient, in critical care for 6 days, with suspected Wernicke-Korsakoff encephalopathy and high risk of refeeding syndrome according to criteria of the National Institute of Health and Clinical Excellence. The subject received enteral nutrition with 14 kcal/kg for the first 3 days, with subsequent increases aiming to achieve a nutritional goal of 25 kcal/kg on day 5.  He also received daily supplementation of thiamine 600mg, folic acid 5mg and pyridoxine 50mg. Blood phosphorus decreased from 3 mg/dL to 2 mg/dL the day after initiating the nutritional plan and normalized by day 3.Discussion: The patient did not present severe hypophosphatemia or clinical manifestations of refeeding syndrome. Hypophosphatemia was resolved by maintaining a stable caloric restriction during the first days. Some professionals consider this restriction as very conservative, and others think that it may lead to achieve significant improvements in mortality reduction.Conclusions: The strategy for assessing the risk of refeeding syndrome, nutritional management and implemented follow-up were successful in preventing the patient from developing a refeeding syndrome.

Nutrition in the ICU: new trends versus old-fashioned standard enteral feeding?

PURPOSE OF REVIEW

The narrative review aims to summarize the relevant studies from the last 2 years and provide contextual information to understand findings.

RECENT FINDINGS

Recent ICU studies have provided insight in the pathophysiology and time course of catabolism, anabolic resistance, and metabolic and endocrine derangements interacting with the provision of calories and proteins.Early provision of high protein intake and caloric overfeeding may confer harm. Refeeding syndrome warrants caloric restriction and to identify patients at risk phosphate monitoring is mandatory.Infectious complications of parenteral nutrition are associated with overfeeding. In recent studies enteral nutrition is no longer superior over parenteral nutrition.Previously reported benefits of glutamine, selenium, and fish oil seem to have vanished in recent studies; however, studies on vitamin C, thiamine, and corticosteroid combinations show promising results.

SUMMARY

Studies from the last 2 years will have marked impact on future nutritional support strategies and practice guidelines for critical care nutrition as they challenge several old-fashioned concepts.

Is refeeding syndrome relevant for critically ill patients?

PURPOSE OF REVIEW

To summarize recent relevant studies regarding refeeding syndrome (RFS) in critically ill patients and provide recommendations for clinical practice.

RECENT FINDINGS

Recent knowledge regarding epidemiology of refeeding syndrome among critically ill patients, how to identify ICU patients at risk, and strategies to reduce the potential negative impact on outcome are discussed.

SUMMARY

RFS is a potentially fatal acute metabolic derangement that ultimately can result in marked morbidity and even mortality. These metabolic derangements in ICU patients differ from otherwise healthy patients with RFS, as there is lack of anabolism. This is because of external stressors inducing a hypercatabolic response among other reasons also reflected by persistent high glucagon despite initiation of feeding. Lack of a proper uniform definition complicates diagnosis and research of RFS. However, refeeding hypophosphatemia is commonly encountered during critical illness. The correlations between risk factors proposed by international guidelines and the occurrence of RFS in ICU patients remains unclear. Therefore, regular phosphate monitoring is recommended. Based on recent trials among critically ill patients, only treatment with supplementation of electrolytes and vitamins seems not sufficient. In addition, caloric restriction for several days and gradual increase of caloric intake over days is recommendable.

Controversies Surrounding Critical Care Nutrition: An Appraisal of Permissive Underfeeding, Protein, and Outcomes

Over the past few years, numerous studies have called into question the optimal dose, timing, composition, and advancement rate of nutrition during the early acute phase of critical illness. These studies suggest permissive underfeeding with slow advancement may be more beneficial than aggressive full feeding. These counterintuitive results were possibly explained by enhanced autophagy, less hyperglycemia, or prevention of refeeding syndrome. This review underscores the controversies surrounding permissive underfeeding, aims to answer whether permissive underfeeding is appropriate for all critically ill patients, describes the impact of optimal protein delivery on critical care outcomes, discusses nutrition risk, and cogitates on the impact of nutrition on critical care outcomes.